Construction and mounting of fuel burner nozzles, especially for gas turbines and like apparatus



Nev. 13, 1951 e. B. R. FEILDEN 2,575,264

CONSTRUCTION AND MOUNTING OF FUEL BURNER NOZZLES, ESPECIALLY FOR GASTURBINES AND LIKE APPARATUS Filed Jan. 14, 1946 4 Sheets-Sheet 1 G. B.R. FEILDEN Nov. 13, 1951 7 2,575,264 CONSTRUCTION AND MOUNTING OF FUELBURNER NOZZLES. ESPECIALLY-FOR GAS TURBINES AND LIKE APPARATUS FiledJan. 14, 1946 4 Sheets-Sheet 2 I I v 8 3 8 g z: S Q 2 NI! n. N: Ill. lIII M. v 7.. 3 m v .A. M n, n a

Nov. 13, 1

ONSTRUCTION PECIALLY Filed Jan. 14, l 6

G. B. R. FEILDEN y 2,575,264 AND MOUNTING OF FUEL BURNER NOZZ FOP. GASTURBINES AND .LIKE APPARAT LES, v

US 4 Sheets-Sheet 3 Nov. 13, 1951 G. B. R. FEILDEN 2,575,264

CONSTRUCTION AND MOUNTING OF FUEL BURNER NOZZLES, ESPECIALLY FOR GASTURBINES AND LIKE APPARATUS Filed Jan. 14, 1946 4 Sheets-Sheet 4 m M U,w

la a! I My m MAM iunfi Patented Nov. 13, 1951 CONSTRUCTION AND MOUNTINGOF FUEL BURNER NOZZLES, ESPECIALLY FOR GAS TURBINES AND LIKE APPARATUSGeoflrey Bertram Robert Feilden, Lutterworth, England, as'signor toPower Jets (Research & Development) Limited, London, England ApplicationJanuary 14, 1948, Serial No. 641,145 In Great Britain January 16, 1945(C1. Gil-39.31)

9 Claims. 1

This invention relates to combustion apparatus more especially of acombustion gas turbine, in which fuel is burnt in a flame tube enclosedwithin an air duct carrying a flow of combustion-supporting air past theflame tube from a point upstream to a point downstream thereof, the fuelbeing injected into the flame tube by a burner mounted for downstreaminjection relative to said flow. The invention is concerned particularlywith the construction and arrangement of fuel burner nozzles, sometimescalled injectors, in such apparatus. It has particular reference to, butis not limited in application to, gas turbines for aircraft propulsionand in relation to that art the invention is especially applicable toengines in what is known as the straight-through category, that is tosay, in which the combustion system is disposed between a compressor anda turbine in such a way that the general sense of direction of gas flowtherethrough is more or less straight, being axial and rearward. In aparticular example of the invention later to be described, the engine isone having a multistage axial flow compressor with an annular diffuseroutlet leading into an annular combustion chamber containing a pluralityof axially directed flame tubes or other combustion elements, the outletof the combustion chamber being united direct to the nozzle ring of theturbine, the whole comprising a gas turbine aero engine which in generalform is symmetrical about its own main axis. This is mentioned, becauseit is to such a case that the invention has at present directapplication, though it will be seen from the following broader statementthat it is not limited thereto. The upstream end of the flame tube has afocal point of attachment at or in the region of the burner nozzle. Inthe art it is common to describe a liquid fuel injection nozzle simplyas a "burner" and this word will be used in the following descriptionand claims. A class of burner to which the invention particularlyrelates is that in which a vortex chamber is employed in which the fuelis caused to swirl and to be ejected through a small orifice from whichit sprays with fine atomization. The invention is concerned with theconstruction of burner, its removability, its mounting and itsassociated ducting and it is an object of the invention to provide aconstruction in which a burner, being itself reasinably simple, compactand easily made, can be removed and replaced with a minimum ofpreliminary movement away from its support and which when mounted issupported robustly so that it can if necessary be used for the furthersupport of a flame tube or its equivalent, whilst the necessity isavoided for specially provided unions with its fuel supply ductingextraneous to its mounting. A burner according to the invention istherefore capable of being mounted direct on part of the enginestructure in an internal and normally inaccessible location. Theinternal mounting of a burner in a gas turbine engine presents manydifllculties which the invention seeks to overcome, but at the same timesuch *intemal mounting has in some designs of engine great inherentadvantage.

According to the invention, in a combustion apparatus of the kindindicated, the burner body is detachably mounted for downstreaminjection on a structural member which extends across the ductingcarrying the gas stream and divides such stream, the fuel supplyconnection to the burner passing through the said structural member andthe burner body forming a point of support for the upstream end of theflame tube into which the fuel is injected, said support being such asto allow axial withdrawal of said flame tube from the burner mounting,and including releasable locking means adapted to retain said flame tubeagainst involuntary displacement. It is intended that the burner shouldbe releasably coupled to the fuel supply connection by means which allowthe removal of such body independently of its fuel supply connection.Thus, in this last connection, a preferred embodiment of the inventionis one in which appropriate fuel ducting opens at a face or platform onthe structural member, and the burner body is applied to said face, thefuel ducting in the burner body registering with that of the structuralmember, and the construction being such that sealed fluid-flowengagement of the respective ducts is effected by the act of mountingthe body on the structural member, without involving pipe unions. 1

In accordance with a further particular form of the invention, thestructural element upon which the burner is mounted is a partitiondividing radially an annular duct, for example, the annular outlet ductof an axial flow compressor, there being a number of such partitionsspaced around the axis of the compressor to deflne axial diffuserpassages and each carrying a burner.

Further features of the invention will become apparent from thefollowingdescription with reference to the accompanying drawings, whichillustrate by way of example two constructional embodiments of theinvention, and in which:

Figure 1 is a part sectional elevation of the forward part of a jetpropulsion gas turbine power 3 unit of a design to which the inventionhas particular application;

Figure 2 is a fragmentary axial section through the outlet annulus of acompressor such as that illustrated in Figure 1, showing the mounting ofa fuel burner and a part of an associated combustion casing or flametube;

Figures 3 and 4 are sections respectively on lines 3-3 and 4-4 of Figure2;

Figure 5 is a view similar to Figure 2, but illustrates a different typeof burner and mounting.

In the power unit illustrated in Figure 1 the principal elements are anaxial flow compressor generally indicated as I supplying air by way ofan outlet annulus generally indicated at 2 to an annular combustionarrangement generally indicated as 3, from which the products ofcombustion and air pass to an axial flow turbine generally indicated as6. The compressor, which is conventionally illustrated since its precisedetails of construction are not relevant to an understanding of thepresent invention, comprises a bladed rotor la and a bladed stator lb,of which the former is connected by a shaft I c with a rotor 6a of theturbine *6 to be driven thereby. In place of the usual stationary guideblading, the axial flow turbine 6 has rotary nozzle blading 6b carriedby a rotor 60 disposed upstream of the rotor 6a and supported throughbearing means Ed on a stationary bearing sleeve lie within which theshaft is has its rear bearing. The nozzleblading 62) carries, radiallyoutwardly, a rotary shroud 61 supporting the interstage guide blading ofthe turbine. The turbine exhausts by a duct 69 terminating in apropulsive J'et (not shown) which is surrounded concentrically by anaugmentor duct 6h in which runs thrust augmenting blading 6i carried bythe nozzle blading 6b.

The combustion arrangement 3 comprises inner and outer walls 3a, 3btogether forming an annular air casing connecting the compressor outlet2 and the turbine i. In the annular air casing are arranged individualflame tubes 4 in which combustion actually takes place, a part of thetotal airflow being admitted for that purpose through suitable ports inthe flame tubes, and the remainder of the air passing around the outsideof the flame tubes to mix with the products of combustion at the outletstherefrom. Each flame tube 5 is supported at its downstream end so as tobe capable of some rearward axial movement by telescoping with a fixedoutlet chute la supported as a part of the main structure by means of ahollow strut 4b, and at its upstream end on a fuel injection nozzle orburner 5, the last mentioned support being shown conventionally inFigure 1 and in greater detail in alternative constructional forms inFigures 2-5.

In accordance with the invention, the fuel burners 5 are mounted each atthe downstream edge of a radial partition or splitter 1 extendingaxially in the compressor outlet annulus 2 (that is to say, in the samegeneral direction as the air stream), there being several of suchpartitions defining axial outlet channels and each mounting a burner.

Each splitter is of substantially aerofoil form in axial cross sectionand has a radial passage 8 which not only accommodates a pipe connectionIn for the external supply, but also constitutes a. passage for the flowof cooling air be tween the outer atmosphere and the inner chamberenclosed by the compressor outlet annulus 2- One or more furtherpassages ll are drilled between the radial passage 8 and the downstreampipe connection i0.

edge of the splitter to provide for fuel connections to the burner.

In the construction illustrated in Figures 2 to 4 there are two suchaxial passages Ii each with a liner l2 of such a length as to projectfrom the splitter body at each end of its passage. At their upstreamends the liners l2 make spigot and socket engagement with correspondingsupply and discharge bores l3 in the pipe connection ID, a fluid-tightseal being obtained by suitable packings as at 14. At their downstreamends the liners l2 make similar engagement with supply and return boresI5 in the burner body 5, sealing rings [6 being again provided. The pipeconnection In is held rigidly to the splitter by bolts ll passingthrough the splitter to engage the These bolts have squared heads Hatapped to receive further bolts i'lb by which the burner body 5 issecured against the splitter I.

The ducting system of the burner is of the kind in which there aretangential swirl ports 18 connected to a swirl chamber I9 having adischarge nozzle 20 and spill duct 2! for the return of surplus fuel tothe supply. The nozzle 20 is formed in a separate end plate held inposition by a sleeve nut 22 having air passages 23 therethrough andprovided with a part-spherical outer rim mating with a correspondingseating of a screwed sleeve 24 to which the upstream end of a flame tube4 is attached, the spherical seating of said sleeve 24 being held inengagement with that of the burner by a threaded'locking sleeve 25 whichis dimensioned and shaped to form an air passage at 26 between itselfand the burner body and com-'- municating with the passages 23, so as tosupply air within the flame tube 4 in the vicinity of the dischargenozzle 20. The sleeve 25 is secured by a wire fastener 25a.

The trailing edge of the splitter is bossed at 21 to provide a planeface for the attachment of the burner body. Whilst, however, the mainbody of the burner is cylindrical, its supporting base is of flattenedcross section and the fuel ducts and bolt holes formed in a line alongit corresponding to the trailing edge of the splitter, so that a minimumof aerodynamic interference 'may be achieved.

In the alternative construction illustrated in Figure 5, a single ductburner is used. In this case the burner support comprises a ferrule 30which is locked in an axial duct ll in the splitter by threadedengagement at one end with the pipe connection In and at the other witha lock nut 3|. The burner body and the ferrule have complementary partspherical seatings which are held in engagement by a union nut 32,whilst the flame tube mounting sleeve 24 is in this case threadedexternally for engagement by a securing nut 34 which holds the sleeve 24against a seating flange 33 on the burner body. The sleeve 24 alsoprovides the air passage 28 to the region of the burner nozzle.

Whilst the invention has been described in its adaptation to aparticular form of engine such description is not limitative; a furtherdirect application of the features of the invention is one in whichburners are required to be mounted internally in a high velocity duct ofair, for example for reheating purposes, forming part of or ancil- .iaryto a gas turbine propulsion installation.

I claim:

1. A combustion apparatus comprising a duct carrying acombustion-supporting air flow, a structural member attached at its endsto opposed walls of the duct and extending across the duct to divide theair flow, through which member passes a fuel supply passage, a flametube enclosed by and extending longitudinally of said duct and locateddownstream of said member, a fuel injection burner receiving fuel fromsaid supply passage detachably mounted on the downstream side of saidmember and having a body extending downstream therefrom, a socket at theupstream end of the flame tube forming with the burner body a spigotingconnection engageable and disengageable in direction of flow, andretaining means to restrain said flame tube against involuntarydisplacement.

2. A combustion apparatus as claimed in claim 1, having means securingsaid burner body di: rectly to said structural member, said fuel supplypassage and body having registering ports which are brought into sealedfluid-flow engagement when said body is secured on said structuralmember.

3. A combustion apparatus as claimed in claim 1, having means securingsaid burner body directly to the said structural membe:, said burnerbody having a base mounting provided with a port, said port registeringwith a complementary port formation of the supply passage andcooperating with said formation to form a spigot and socket joint, andsaid ports being brought into sealed fluid-flow engagement when saidbody is secured on said structural member.

4. A combustion apparatus as claimed in claim 1, having a supplyconnection projecting from said structural member, said burner bodybeing directly and releasably connected thereto.

5. A combustion apparatus comprising an annular duct carrying acombustion-supporting air flow, a plurality of partitions attached attheir ends to the inner and outer walls respectively of the duct andextending radially across the duct to divide it into segments, througheach of which partitions passes a fuel supply passage, a like number offlame tubes annularly disposed within and extending longitudinally ofsaid duct, each being located downstream of one of said partitions, alike number of fuel injection burners, each receiving fuel from one ofsaid supply passages and being detachably mounted on the downstream sideof a partition and having a body extending downstream therefrom, asocket at the upstream end of each flame tube forming with the burnerbody a spigoting connection engageable and disengageable in thedirection of flow, and retaining means to restrain the flame tubesagainst involuntary displacement.

6. A combustion apparatus comprising an axial flow compressor having anannular axially directed outlet, an annular duct receiving a combustionsupporting air flow from said compressor outlet, a plurality ofpartitions attached at their ends to the inner and outer wallsrespectively of the outlet, and extending radially across the outlet todivide it into segments, through each of which partitions passes a fuelsupply pas-v sage. a like number of flame tubes annularly disposedwithin and extending longitud nally of said duct. each flame tube beingheat -er downstream of one of said partitions a like number of fuelinjection burners. each receiving fuel from one of said supply passagesand being detachably mounted on the downstream side of a partition andhaving a body extending downstream therefrom, a socket at the upstreamend of each flame tube forming with the burner body a spigotingconnection engageable and disengageable in the direction of flow, andretaining means to restrain the flame tubes against involuntary displacement.

7. A gas turbine plant comprising an axial flow compressor having anannular axially directed outlet, an annular duct receiving the outputfrom said compressor outlet, a turbine nozzle annulus receiving theoutput from saidduct and an axial flow turbine, said compressor, duct,nozzle annulus and turbine being coaxially arranged for substantiallystraight through flow, a plurality of partitions attached at their endsto the inner and outer walls respectively of the outlet, and extendingradially across the outlet to divide it into segments, a like number offlame tubes annularly disposed within and extending longitudinally ofsaid duct, each flame tube being located downstream of one of saidpartitions, a like number of fuel injection burners, each beingdetachably mounted on the downstream side of a partition and having abody extending downstream therefrom, a socket at the upstream end ofeach flame tube forming with the burner body a spigoting connectionengageable and disengageable in the direction of flow, and retainingmeans to restrain the flame tubes against involuntary dis lacement. 8. Agas turbine plant as claimed in claim 7, wherein each partition elementsupporting a burner has a radiallv extending passa e therein and anaxially directed aperture in its down stream wall which communicateswith said radial passage, and wherein standing fuel supply ducting isaccommodated in the passages thus formed, and the burner is mounted onsaid do nstream wall. said burner having fuel receivin d ct n matingwith said fuel connections to receive fuel therefrom.

9. A gas turbine plant as claimed in claim 8, wherein said fuel sunnlyducting includes a tube extending through the passa e formed in saiddownstream wall and nro ectine therefrom at each end, said nro ectionsformin with complementary formations of the burner bndv and a fuelsunnlv pine connection in said radial passage a spigot and socket joint.

GEOFFREY BERTRAM ROBERT FEILDEN.

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